Radiographic Film

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Radiographic Film
Arino Celjhon B.
Joanna Miranda Celjhon Ariño
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X-ray film

• Film is a media that makes a permanent record of
  the image.
• Image recorded on film is caused by exposure to
  photons
• Radiographic film is/was most common image
  receptor

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Radiographic Film Base

• First Film
• Glass Plates
• WW1
• Cellulose Nitrate
• Highly Flammable
• Easily Torn
• Responsible for many fires in hospital basements
• Cellulose Triacetate

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Film construction BASE

• Made of polyester plastic
• Must be clear, strong, consistent thickness
• Tinted pale blue or blue-gray (reduces eye
  strain)
• Coated on 1 or 2 sides with emulsion

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Film Construction - EMULSION

• Film emulsion can be on one side or both sides of
  base (single emulsion/double emulsion)
• Protective overcoat layered on top of emulsion
• Emulsion is a gelatin, containing the film
  crystals
• Emulsion is the active layer of the film

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FILM COMPOSITION

• SINGLE OR DOUBLE EMULSION
• COATED ON A BASE
• EMULSION GELATIN
• WITH SILBER HALIDE CRYSTALS
• BASE SUPPORT (POLYESTER)

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FILM EMULSION

• Made of mixture of gelatin silver halide
  crystals (fluorine, chlorine, bromine, iodine)
• Most x-ray film emulsions are made of
• Silver Bromide (98)
• Silver Iodide (2)
• Photographically active layer activated by
  light radiation to create image

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Silver Halide Crystals

• Crystals are cubic in structure
• Crystal lattice containing ions

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FILM CONSTRUCTION

• Film is manufacture to have specific
  characteristics of speed, contrast and
  resolution.
• Film is also manufactured to be sensitive to
  specific colors of light spectral matching
• Direct-exposure film thicker emulsion with more
  silver halide crystals

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FILM CONSTRUCTION

• BASE WITH EMULSION
• CAN BE ON 1 (SINGLE EMULSION)
• OR 2 SIDES (DOUBLE EMULSION)
• MUST BE MATCHED WOTH 1 OR 2 SIDED INTENSIFYING
  SCREENS

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PICTURE OF CROSS SECTION OF FILM
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2 CLASSIFICATIONS OF FILMS

• PANCHROMATIC PAN LIKE PANORAMIC COLORS
  SENSITIVE TO ALL COLORS OF LIGHT
• ORTHOCHROMATIC MOST COMMONLY USED IN MEDICAL
  IMAGING NOT SENSITIVE TO THE RED SPECTRUM
  MOSTLY ON BLUE AND GREEN

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IMAGE FORMATION

• X-RAY PHOTONS CONVERTED TO LIGHT PHOTONS
• IMAGE BEFORE PROCESSING LATENT IMAGE
• MADE VISIBLE BY CHEMICAL PROCESSING
• AFTER PROPER CHEMICAL PROCESSING MANIFEST IMAGE

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IMAGE ON FILM

• SINGLE EMULSION BETTER DETAIL
• DOUBLE EMULSION LESS DETAIL
• PARALLAX
• WITH DOUBLE EMULSION AN IMAGE IS CREATED ON
  BOTH EMULSIONS- THEN SUPERIMPOSED SLIGHT
  BLURRING OF EDGES

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RADIATION INTERACTS RELEASING ELECTRONS

• SILVER ATOMS BUILDUP AT THE SENSITIVITY CENTER,
  BUILDING THE LATENT IMAGE CENTER
• THE GROUP OF SILVER ATOMS IS CALLED THE LATENT
  IMAGE CENTER

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LIGHT VS DARK AREAS ON FILM

• DARK SPOTS- SLIBER HALIDE CRYSTALS THAT HAVE BEEN
  EXPOSED TO PHOTONS TURN TO BLACK METALLIC
  SILVER AFTER PROCESSING
• LIGHT AREAS- NO CRYSTALS EXPOSED SILVER HALIDE
  IS WASHED AWAY WITH PROCESSING

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End